For efficient operation of a macrocell base station in a mobile communication system, introduction of a mobile fronthaul in which an antenna part and a baseband signal processing part are separated has been in progress. A common public radio interface (CPRI) is a de facto standard of a wired signal that connects a device corresponding to the antenna part and a device corresponding to the baseband signal processing part. Along with a traffic increase in a wireless terminal such as a smartphone, an increase in capacity of an optical transmission link that connects an antenna device and a baseband signal processing device is also demanded. Additionally, a method for efficiently multiplexing and transferring a CPRI signal, which is transmitted and received in the optical transmission link between the devices, while holding some signal quality such as a delay or error rate is also demanded.
In an optical transport network (OTN) that is a transmission standard in optical communication, it is possible to admit various kinds of client signals and to improve transmission quality of a signal by providing a parity for error correction.
In the OTN standard, a number of multiplexing methods are prescribed to efficiently and economically transfer various kinds of many client signals including CPRI. For example, in Non-Patent Literature 1, there is described a set value or the like in a case where signals such as CPRI option 3 of 2.458 Gbit/s and CPRI option 4 of 3.072 Gbit/s are contained in an optical channel transport unit (OTU) frame using a generic mapping procedure (GMP).